Abstract

The use of aluminum metal for replacing iron and steel is more increasing. This is because aluminum has several superiorites such as light and easy to be composed. Yet, aluminum tends not to withstand to scratch that may decline the aesthetics characteristic and mechanical capacity.
Aluminum has capacity to form naturally oxide layer that provide protection to corrosion and scratch, yet this layer is very thin. Therefore, electrolysis processes needed to increase oxidation on aluminum called as Anodizing.
In the process of anodizing, electrolite solution is used, that is sulphuric acid. Concentration of sulphuric acid has influence on the hardness of aluminum surface as result of anodizing. Therefore, further research is important about variation of sulphurid acid concentration. Thus, we can get the optimum of aluminum hardness as result of anodizing.
Result of hardness test by using sonohard showed that there is optimum hardness point taken from variation of sulphuric acid concentration. Sulphuric acid concentration of 15% with anodizing time of 60 minutes and electrical current of 12 V DC result is optimum aluminum hardness of 734.4 Hv.